using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;
 
class Program
{
    public void Proc()
    {
        Reader.IsDebug = false;
        int[] inpt = Reader.GetInt();
        int cardCount = inpt[0];
        int shuffleCount = inpt[1];
        
        List<int> cards = new List<int>();
        for(int i=1; i<=cardCount; i++) {
            cards.Add(i);
        }
        
        int[] shuffle = Reader.GetInt();
        for(int i=0; i<shuffleCount; i++) {
            int idx = shuffle[i] - 1;
            int tmp = cards[idx];
            cards.RemoveAt(idx);
            cards.Insert(0, tmp);
        }
        
        Console.WriteLine(cards[0]);

    }
 
 
 
    public class Reader
    {
        public static bool IsDebug = true;
        private static String PlainInput = @"




10 8
6 10 4 2 7 1 4 3




 
";
        private static System.IO.StringReader Sr = null;
        public static string ReadLine()
        {
            if (IsDebug)
            {
                if (Sr == null)
                {
                    Sr = new System.IO.StringReader(PlainInput.Trim());
                }
                return Sr.ReadLine();
            }
            else
            {
                return Console.ReadLine();
            }
        }
        public static int[] GetInt(char delimiter = ' ', bool trim = false)
        {
            string inptStr = ReadLine();
            if (trim)
            {
                inptStr = inptStr.Trim();
            }
            string[] inpt = inptStr.Split(delimiter);
            int[] ret = new int[inpt.Length];
            for (int i = 0; i < inpt.Length; i++)
            {
                ret[i] = int.Parse(inpt[i]);
            }
            return ret;
        }
    }
    static void Main()
    {
        Program prg = new Program();
        prg.Proc();
    }
}